From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B8F14C4321D for ; Fri, 17 Aug 2018 16:27:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 680D02154F for ; Fri, 17 Aug 2018 16:27:37 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 680D02154F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=bootlin.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727856AbeHQTbe (ORCPT ); Fri, 17 Aug 2018 15:31:34 -0400 Received: from mail.bootlin.com ([62.4.15.54]:56373 "EHLO mail.bootlin.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727160AbeHQTbe (ORCPT ); Fri, 17 Aug 2018 15:31:34 -0400 Received: by mail.bootlin.com (Postfix, from userid 110) id 8DE61215D9; Fri, 17 Aug 2018 18:27:31 +0200 (CEST) Received: from bbrezillon (91-160-177-164.subs.proxad.net [91.160.177.164]) by mail.bootlin.com (Postfix) with ESMTPSA id B7AAD215D6; Fri, 17 Aug 2018 18:27:20 +0200 (CEST) Date: Fri, 17 Aug 2018 18:27:20 +0200 From: Boris Brezillon To: Bartosz Golaszewski Cc: Jonathan Corbet , Sekhar Nori , Kevin Hilman , Russell King , Arnd Bergmann , Greg Kroah-Hartman , David Woodhouse , Brian Norris , Marek Vasut , Richard Weinberger , Grygorii Strashko , "David S . Miller" , Srinivas Kandagatla , Naren , Mauro Carvalho Chehab , Andrew Morton , Lukas Wunner , Dan Carpenter , Florian Fainelli , Ivan Khoronzhuk , Sven Van Asbroeck , Paolo Abeni , Alban Bedel , Rob Herring , David Lechner , Andrew Lunn , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-i2c@vger.kernel.org, linux-mtd@lists.infradead.org, linux-omap@vger.kernel.org, netdev@vger.kernel.org, Bartosz Golaszewski Subject: Re: [PATCH v2 06/29] mtd: Add support for reading MTD devices via the nvmem API Message-ID: <20180817182720.6a6e5e8e@bbrezillon> In-Reply-To: <20180810080526.27207-7-brgl@bgdev.pl> References: <20180810080526.27207-1-brgl@bgdev.pl> <20180810080526.27207-7-brgl@bgdev.pl> X-Mailer: Claws Mail 3.15.0-dirty (GTK+ 2.24.31; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Bartosz, On Fri, 10 Aug 2018 10:05:03 +0200 Bartosz Golaszewski wrote: > From: Alban Bedel > > Allow drivers that use the nvmem API to read data stored on MTD devices. > For this the mtd devices are registered as read-only NVMEM providers. > > Signed-off-by: Alban Bedel > [Bartosz: > - use the managed variant of nvmem_register(), > - set the nvmem name] > Signed-off-by: Bartosz Golaszewski What happened to the 2 other patches of Alban's series? I'd really like the DT case to be handled/agreed on in the same patchset, but IIRC, Alban and Srinivas disagreed on how this should be represented. I hope this time we'll come to an agreement, because the MTD <-> NVMEM glue has been floating around for quite some time... Regards, Boris > --- > drivers/mtd/Kconfig | 1 + > drivers/mtd/mtdcore.c | 50 +++++++++++++++++++++++++++++++++++++++++ > include/linux/mtd/mtd.h | 2 ++ > 3 files changed, 53 insertions(+) > > diff --git a/drivers/mtd/Kconfig b/drivers/mtd/Kconfig > index 46ab7feec6b6..f5549482d0df 100644 > --- a/drivers/mtd/Kconfig > +++ b/drivers/mtd/Kconfig > @@ -1,5 +1,6 @@ > menuconfig MTD > tristate "Memory Technology Device (MTD) support" > + imply NVMEM > help > Memory Technology Devices are flash, RAM and similar chips, often > used for solid state file systems on embedded devices. This option > diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c > index 42395df06be9..a57302eaceb5 100644 > --- a/drivers/mtd/mtdcore.c > +++ b/drivers/mtd/mtdcore.c > @@ -488,6 +488,49 @@ int mtd_pairing_groups(struct mtd_info *mtd) > } > EXPORT_SYMBOL_GPL(mtd_pairing_groups); > > +static int mtd_nvmem_reg_read(void *priv, unsigned int offset, > + void *val, size_t bytes) > +{ > + struct mtd_info *mtd = priv; > + size_t retlen; > + int err; > + > + err = mtd_read(mtd, offset, bytes, &retlen, val); > + if (err && err != -EUCLEAN) > + return err; > + > + return retlen == bytes ? 0 : -EIO; > +} > + > +static int mtd_nvmem_add(struct mtd_info *mtd) > +{ > + struct nvmem_config config = { }; > + > + config.dev = &mtd->dev; > + config.owner = THIS_MODULE; > + config.name = mtd->name; > + config.reg_read = mtd_nvmem_reg_read; > + config.size = mtd->size; > + config.word_size = 1; > + config.stride = 1; > + config.read_only = true; > + config.root_only = true; > + config.priv = mtd; > + > + mtd->nvmem = devm_nvmem_register(&mtd->dev, &config); > + if (IS_ERR(mtd->nvmem)) { > + /* Just ignore if there is no NVMEM support in the kernel */ > + if (PTR_ERR(mtd->nvmem) == -ENOSYS) { > + mtd->nvmem = NULL; > + } else { > + dev_err(&mtd->dev, "Failed to register NVMEM device\n"); > + return PTR_ERR(mtd->nvmem); > + } > + } > + > + return 0; > +} > + > static struct dentry *dfs_dir_mtd; > > /** > @@ -570,6 +613,11 @@ int add_mtd_device(struct mtd_info *mtd) > if (error) > goto fail_added; > > + /* Add the nvmem provider */ > + error = mtd_nvmem_add(mtd); > + if (error) > + goto fail_nvmem_add; > + > if (!IS_ERR_OR_NULL(dfs_dir_mtd)) { > mtd->dbg.dfs_dir = debugfs_create_dir(dev_name(&mtd->dev), dfs_dir_mtd); > if (IS_ERR_OR_NULL(mtd->dbg.dfs_dir)) { > @@ -595,6 +643,8 @@ int add_mtd_device(struct mtd_info *mtd) > __module_get(THIS_MODULE); > return 0; > > +fail_nvmem_add: > + device_unregister(&mtd->dev); > fail_added: > of_node_put(mtd_get_of_node(mtd)); > idr_remove(&mtd_idr, i); > diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h > index a86c4fa93115..8121c6582285 100644 > --- a/include/linux/mtd/mtd.h > +++ b/include/linux/mtd/mtd.h > @@ -25,6 +25,7 @@ > #include > #include > #include > +#include > > #include > > @@ -339,6 +340,7 @@ struct mtd_info { > struct device dev; > int usecount; > struct mtd_debug_info dbg; > + struct nvmem_device *nvmem; > }; > > int mtd_ooblayout_ecc(struct mtd_info *mtd, int section,